Critique of Dembski's"Intelligent Design is Not Optimal Design"

By Wesley R. Elsberry

Posted May 6, 2002

William A. Dembski continues his series of essays advocating an
Intelligent Design Creationist (IDC) stance. In this one, he recycles
Paul Nelson's arguments concerning evolutionary arguments about
optimality and suboptimality. Dembski considers three categories of
design: apparent, intelligent (or actual), and optimal. Apparent
design is the limited (according to Dembski) class of design which can
be accomplished via natural processes unaided by agents. Intelligent
design is accomplished by an agent, but not necessarily an infinitely
intelligent agent. The term "actual" as applied by Dembski has a
history of juxtaposition with "apparent" in his past essays, but in
this essay the flavor seems to draw more from Dembski's description of
intelligent designers making realizable designs in the presence of
conflicting constraints. Optimal design as described by Dembski
refers to a class of design which ignores the prevailing constraints
that limit actual design, and thus can only be considered to apply to
some ideal plane, not to any reality in which agents operate.

There are a variety of problems in this latest essay. As implied
above, terminological issues pose not inconsiderable problems of their
own. Part of the problem is that the topic of optimality is not
simply a tabula rasa awaiting the impress of an IDC intellect to shape
it. A quite considerable literature exists which explores various
aspects of optimality as it applies to biological issues. As the
literature on optimal foraging theory makes clear, optimality is to
be considered as finding the best approach with respect to a set of
relevant constraints. In other words, "optimality" as it is already
used by biologists corresponds rather closely to the description that
Dembski gives for "constrained optimization". "Constrained
optimization" is touted by Dembski as a feature of designs produced by
intelligent designers and thus characteristic of actual design. But
now we have the curious situation where the theologian climbs the
mountain - and finds the biologists already ensconced there. The
"optimality" discussed by biologists is "constrained optimization",
and thus shares the properties that Dembski asserts for "actual
design".

The deployment of arguments that stray into theological areas is a
matter of concern for Dembski. The mere fact that scientists do make
arguments based upon theological themata is taken as a weakness by
Nelson and Dembski. But the intrusion of theological issues into the
scientific arena is not simply a matter of ancient history. To make
arguments that plainly seek to advance theological goals in relation
to science and then critique scientists for having the temerity to
venture a response on theological turf seems to me to have the flavor
of chutzpah. What is apparently galling to Nelson and Dembski is that
the scientists have been so effective when making those theological
arguments.

Dembski proceeds to bash Stephen Jay Gould for Gould's critiques which
employ considerations of optimality, attributing to Gould the use of
"optimality" as referencing some unachievable ideal design. This is a
fundamental error, as Gould is not doing this. Gould's use of
optimality is consistent with other biological usage, and thus
comports with the real-world category of "constrained optimization".
Gould, Dembski claims, cannot critique a designer without having
knowledge of the objectives of the designer. This is erroneous.
There exist valid arguments which make designers susceptible to
criticism on the basis of their designs. Specifically, one can
reliably infer inconsistency on the part of a designer whose range of
designs incorporate modules whose functional efficiency may vary
widely, but which are deployed to achieve the same functions in
different organisms. Dembski offers an appeal to ignorance as a
defense against this kind of argument. According to Dembski, we
cannot know that a particular design could actually be improved, or
that putting the improvement in place would not create deficiencies
elsewhere. This is a particularly weak defense. Consider the case of
the panda's thumb, which Dembski addresses in his essay. If the same
designer produced both the thumb in primates and the thumb of pandas,
vague hints that problems might arise were the panda to be fitted with
a primate-style thumb seem ineffective as a rejoinder. If the same
designer is responsible for both designs, that designer is
inconsistent. Period.

Tom Scharle has developed this sort of argument in posts on
talk.origins. Instead of concluding inconsistency on the part of a
single designer, though, Scharle uses such a finding as support for
the notion that multiple designers are responsible. What Intelligent
Design Creation conjectures seem to naturally lead to is a kind of
polytheism, or at least poly-designer-ism. The plethora of design
approaches to solve the same functional problems in biology bespeaks a
similar plethora of designers, or a designer with a serious case of
multiple personality disorder. What it does not bespeak is a single
designer utilizing the concept of "intelligent re-use".

Dembski claims that suboptimality arguments have gained their appeal
by abandonment of a scientific approach and adoption of a theological
approach. Dembski says that the question of how could an existing
structure be improved is set aside in favor of asking what sort of God
or designer would create such a structure. This is, I believe, a
misrepresentation. The question of how a particular structure could
be improved is almost always addressed, although it may be more
implicit than explicit in some cases. In the case of discussion of
thumbs, for example, we have a variety of different thumb designs that
are actualized. We don't have to wonder *how* a panda's thumb might
be improved; we know from the digits that operate the space bars of
our typewriters and computers where an improvement can be found. That
it is an improvement could only be denied by the ideologically
committed. On measures of range of motion, flexibility, and strength
there is no question of its superiority. As for the question of what
sort of God or designer would create such a structure, I believe
Dembski has not quite formulated the correct question. Instead, the
question asked is what sort of designer, having designed both
structure A and structure B having shared function X where structure
A is clearly superior to structure B, decides to actually deploy
structure B anyway. The answer is, plainly, an inconsistent designer.

Dembski again touts "reliable indicators of design". There is an
almost desperate quality to the race to distance design detection from
anything that might lead to consideration of attributes of the
designer. But the fact is that the "reliability" is simply asserted
rather than demonstrated. When no information is available concerning
the actual cause of an event, Dembski's "complexity-specification"
criterion is completely powerless to distinguish between that event
being the product of natural causes (having the "appearance of
design") and the event being the product of agent causation (having
the attribute of "actual design"). (See my previous criticisms of
Dembski's META essays, linked from
The Anti-Evolutionists: William A. Dembski.)

Dembski's proposed connection between suboptimality arguments and the
problem of evil ignores the actual power of suboptimality arguments.
The mere existence of systems which display "constrained optimization"
does not argue for intelligent agents at the expense of natural
selection. Dembski identifies "choice" as the hallmark of intelligent
agent causation, but ignores the fact that "selection" is a synonym
for "choice" in this regard. Natural selection, it turns out, has all
the properties that Dembski claims for intelligent agents in "The
Design Inference". It should surprise no one that the Design
Inference has no means of distinguishing events due to intelligent
agency from those due to the operation of natural selection.